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+.. include:: <isonum.txt>
+
+
+The SI476x Driver
+=================
+
+Copyright |copy| 2013 Andrey Smirnov <andrew.smirnov@gmail.com>
+
+TODO for the driver
+-------------------
+
+- According to the SiLabs' datasheet it is possible to update the
+ firmware of the radio chip in the run-time, thus bringing it to the
+ most recent version. Unfortunately I couldn't find any mentioning of
+ the said firmware update for the old chips that I tested the driver
+ against, so for chips like that the driver only exposes the old
+ functionality.
+
+
+Parameters exposed over debugfs
+-------------------------------
+SI476x allow user to get multiple characteristics that can be very
+useful for EoL testing/RF performance estimation, parameters that have
+very little to do with V4L2 subsystem. Such parameters are exposed via
+debugfs and can be accessed via regular file I/O operations.
+
+The drivers exposes following files:
+
+* /sys/kernel/debug/<device-name>/acf
+ This file contains ACF(Automatically Controlled Features) status
+ information. The contents of the file is binary data of the
+ following layout:
+
+ ============= ============== ====================================
+ Offset Name Description
+ ============= ============== ====================================
+ 0x00 blend_int Flag, set when stereo separation has
+ crossed below the blend threshold
+ 0x01 hblend_int Flag, set when HiBlend cutoff
+ frequency is lower than threshold
+ 0x02 hicut_int Flag, set when HiCut cutoff
+ frequency is lower than threshold
+ 0x03 chbw_int Flag, set when channel filter
+ bandwidth is less than threshold
+ 0x04 softmute_int Flag indicating that softmute
+ attenuation has increased above
+ softmute threshold
+ 0x05 smute 0 - Audio is not soft muted
+ 1 - Audio is soft muted
+ 0x06 smattn Soft mute attenuation level in dB
+ 0x07 chbw Channel filter bandwidth in kHz
+ 0x08 hicut HiCut cutoff frequency in units of
+ 100Hz
+ 0x09 hiblend HiBlend cutoff frequency in units
+ of 100 Hz
+ 0x10 pilot 0 - Stereo pilot is not present
+ 1 - Stereo pilot is present
+ 0x11 stblend Stereo blend in %
+ ============= ============== ====================================
+
+
+* /sys/kernel/debug/<device-name>/rds_blckcnt
+ This file contains statistics about RDS receptions. It's binary data
+ has the following layout:
+
+ ============= ============== ====================================
+ Offset Name Description
+ ============= ============== ====================================
+ 0x00 expected Number of expected RDS blocks
+ 0x02 received Number of received RDS blocks
+ 0x04 uncorrectable Number of uncorrectable RDS blocks
+ ============= ============== ====================================
+
+* /sys/kernel/debug/<device-name>/agc
+ This file contains information about parameters pertaining to
+ AGC(Automatic Gain Control)
+
+ The layout is:
+
+ ============= ============== ====================================
+ Offset Name Description
+ ============= ============== ====================================
+ 0x00 mxhi 0 - FM Mixer PD high threshold is
+ not tripped
+ 1 - FM Mixer PD high threshold is
+ tripped
+ 0x01 mxlo ditto for FM Mixer PD low
+ 0x02 lnahi ditto for FM LNA PD high
+ 0x03 lnalo ditto for FM LNA PD low
+ 0x04 fmagc1 FMAGC1 attenuator resistance
+ (see datasheet for more detail)
+ 0x05 fmagc2 ditto for FMAGC2
+ 0x06 pgagain PGA gain in dB
+ 0x07 fmwblang FM/WB LNA Gain in dB
+ ============= ============== ====================================
+
+* /sys/kernel/debug/<device-name>/rsq
+ This file contains information about parameters pertaining to
+ RSQ(Received Signal Quality)
+
+ The layout is:
+
+ ============= ============== ====================================
+ Offset Name Description
+ ============= ============== ====================================
+ 0x00 multhint 0 - multipath value has not crossed
+ the Multipath high threshold
+ 1 - multipath value has crossed
+ the Multipath high threshold
+ 0x01 multlint ditto for Multipath low threshold
+ 0x02 snrhint 0 - received signal's SNR has not
+ crossed high threshold
+ 1 - received signal's SNR has
+ crossed high threshold
+ 0x03 snrlint ditto for low threshold
+ 0x04 rssihint ditto for RSSI high threshold
+ 0x05 rssilint ditto for RSSI low threshold
+ 0x06 bltf Flag indicating if seek command
+ reached/wrapped seek band limit
+ 0x07 snr_ready Indicates that SNR metrics is ready
+ 0x08 rssiready ditto for RSSI metrics
+ 0x09 injside 0 - Low-side injection is being used
+ 1 - High-side injection is used
+ 0x10 afcrl Flag indicating if AFC rails
+ 0x11 valid Flag indicating if channel is valid
+ 0x12 readfreq Current tuned frequency
+ 0x14 freqoff Signed frequency offset in units of
+ 2ppm
+ 0x15 rssi Signed value of RSSI in dBuV
+ 0x16 snr Signed RF SNR in dB
+ 0x17 issi Signed Image Strength Signal
+ indicator
+ 0x18 lassi Signed Low side adjacent Channel
+ Strength indicator
+ 0x19 hassi ditto fpr High side
+ 0x20 mult Multipath indicator
+ 0x21 dev Frequency deviation
+ 0x24 assi Adjacent channel SSI
+ 0x25 usn Ultrasonic noise indicator
+ 0x26 pilotdev Pilot deviation in units of 100 Hz
+ 0x27 rdsdev ditto for RDS
+ 0x28 assidev ditto for ASSI
+ 0x29 strongdev Frequency deviation
+ 0x30 rdspi RDS PI code
+ ============= ============== ====================================
+
+* /sys/kernel/debug/<device-name>/rsq_primary
+ This file contains information about parameters pertaining to
+ RSQ(Received Signal Quality) for primary tuner only. Layout is as
+ the one above.